Don't get me wrong, my dream car is a midnight blue 240Z with an L28 turbo with 600hp, but for that amount of cash right up people wouldn't really bother with old school... Unless like you say; they will be entering tournaments/races etc. Which then I believe people would build up their own car from scratch?
There's a rare race spec 280zx 2-seater on carsales for 18k, which is a reasonable price for that car, but 45k+
That 2s 280ZX has been rallied I think, be careful as to body damage.